Rate of Flow Question

[MKCindy]

I have a 40 Gal. Breeder with a Mag 5 return (1- 90 degree bend), Skimmer and 2- Kor 4. One of the Kor only runs 6 hours a day. I know it is too much flow, I have adjusted them to minimize sand storms, but there is still a lot of shifting sand. I use to run just the one Kor 4 and had dead spots.
A Kor 4 is 1200, Kor 3 is 850 and Kor 2 is 600. What is the formula to decide what is enough?

[erikharrison]

Face them lengthwise at each other, or get the tornado thing going on. Use the mag 5 for surface disturbance. On my back left corner I have 2 #4s facing lengthwise and one in the middle right side. I too have a mag 5 just for surface disturbance. I have one tang in particular that loves swimming right into the brunt of that 2400gph as I now leave all three powerheads on during the day. I am going to add another soon and will be using some smaller ones to help with suspension so no detritus builds up. The only thing I think would be bad is if you have fish that don't like that much flow. I have a sea goblin and two huge engineer gobies that all stay at the bottom, so I have my powerheads directed to accomodate them. I had a flasher wrasse and it did not like the flow at all. My tangs LOVE it as well as my other fish, sometimes even the puffer.
:)

[caferacermike]

I don't think it's to much flow at all. It will help keep detritus suspended and not decaying in your rock work or sand bed. I run about 5,000GPH from a handful of Tunze and Eheim pumps in my 75g.

[MKCindy]

Thanks, I had them on opposite sides facing the center of the front glass. I'll do some rearranging. My baby Clown is the only one I worry about, but he has been hanging out behind the Dragons Breath, it works as a buffer. LOL